Framework for Balanced Mix Design NCHRP 20-07/Task 406

Transcription

1 Click here to begin the survey Framework for Balanced Mix Design NCHRP 20-07/Task 406

2 Balanced Mix Design (BMD) BMD is defined as an asphalt mix design using performance tests on appropriately conditioned specimens that address multiple modes of distress taking into consideration mix aging, traffic, climate and location within the pavement structure.

3 Objective Develop a framework that addresses alternate approaches to devise and implement BMD procedures incorporating performance testing and criteria. The framework shall be in the format of an AASHTO recommended practice and will provide DOTs with options on which performance tests to use and how the tests can be used in the overall mix design framework.

4 Balanced Mix Design Approaches 1 2 Volumetric Design with Performance Verification 3 Performance-Modified Volumetric Mix Design Performance Design

5 Does your agency CURRENTLY use a BMD approach? Approach 1 Approach 2 Use a performance test, but not a true BMD approach

6 On which types of asphalt mixtures does your agency use BMD? Answers (DOT) All mixes Premium mixes (e.g., SMA, HiMA) # Response 2 (CA, IL) 3 (IA, NJ, TX) High traffic mixes 0 Bridge deck mixes 1 (NJ) RAP/RAS mixes 0

7 Will your agency consider modifying the current mix design procedure with a BMD approach? Answers (DOT) Yes, Approach 1 - Volumetric Design with Performance Verification # Response Yes, Approach 2 - Performance-Modified Volumetric Design 0 Yes, Approach 3 - Performance Design 1 Yes, Approach not determined 19 No 3 5

8 What types of pavement distress does your agency want to address with mixture performance tests? Answers (DOT) # (%) Response Fatigue cracking 36 (84%) Rutting 32 (74%) Thermal cracking 29 (67%) Moisture damage 26 (60%) Reflection cracking 24 (56%) Raveling 22 (51%) Others (block cracking, slippage, etc.) 22 (51%)

9 Which of the following bottom-up fatigue cracking tests is used in your CURRENT mix design specs? Answers (DOT) # (%) Response Test not required 34 (85%) Flexural Bending Beam Fatigue Test (BBF) 3 (8%) SCB at Intermediate Temperature (SCB-Jc) 1 (3%) Illinois Flexibility Index Test (I-FIT) 1 (3%) Texas Overlay Test (OT) 1 (3%) Direct Tension Cyclic Fatigue Test (S-VECD) 0 IDT Fracture Energy Test 0

10 Which of the following performance tests do you think have the most potential to address bottomup fatigue cracking? DOT Contractor

11 Which of the following top-down fatigue cracking tests is used in your CURRENT mix design specs? Answers (DOT) # (%) Response Test not required 39 (98%) Illinois Flexibility Index Test (I-FIT) 1 (3%) Direct Tension Cyclic Fatigue Test (S-VECD) 0 IDT Energy Ratio Test (IDT ER) 0

12 Which of the following performance tests do you think have the most potential to address top-down fatigue cracking? DOT Contractor

13 Which of the following rutting tests is used in your CURRENT mix design specifications? Answers (DOT) # (%) Response Test not required 17 (43%) Asphalt Pavement Analyzer (APA) 10 (25%) Hamburg Wheel Tracking Test (HWTT) 10 (25%) Hveem Stabilometer 2 (5%) Flow Number (FN) 1 (3%) Superpave Shear Tester (SST) 0

14 Current Use of Rutting Tests

15 Which of the following performance tests do you think have the most potential to address rutting? DOT Contractor

16 Which of the following thermal cracking tests is used in your CURRENT mix design specifications? Answers (DOT) # (%) Response Test not required 37 (93%) Disk-Shaped Compact Tension Test (DCT) 3 (8%) Semi-Circular Bend (SCB) Test at Low Temperature 0 Indirect Tensile (IDT) Creep Compliance and Strength Test 0 Thermal Stress Restrained Specimen Test (TSRST) 0

17 Which of the following performance tests do you think have the most potential to address thermal cracking? DOT Contractor

18 Which of the following reflection cracking tests is used in your CURRENT mix design specifications? Answers (DOT) # (%) Response Test not required 37 (93%) Texas Overlay Test (OT) 2 (5%) Illinois Flexibility Index Test (I-FIT) 1 (3%) Disk-Shaped Compact Tension Test (DCT) 0

19 Which of the following performance tests do you think have the most potential to address reflection cracking? DOT Contractor

20 Which of the following moisture damage tests is used in your CURRENT mix design specifications? Answers (DOT) # (%) Response Tensile Strength Ratio (TSR) 29 (73%) Hamburg Wheel Tracking Test (HWTT) 5 (13%) Test not required 3 (8%) Immersion Compression Test 2 (5%) Asphalt Film Retention Test 1 (3%)

21 Current Use of Moisture Damage Tests

22 Which of the following performance tests do you think have the most potential to address moisture damage? DOT Contractor

23 What are your concerns regarding the implementation of BMD? DOT Contractor

24 Please rate the following BMD related research topics based on their level of importance. 1= not important at all 5 = very important DOT Contractor

25 2017 Webinar Series Balanced Mix Design (BMD) for Asphalt Mixtures Nov. 2, 9, and 16 (Three Consecutive Thursdays) at 2 PM EST Part 1: Nov. 2 Background on the need for BMD, different approaches, and path to implementation Dr. Shane Buchanan Oldcastle Materials Part 2: Nov. 9 Developing a BMD framework, current gaps and research needs, how to get started on BMD now Dr. Randy West NCAT Part 3: Nov. 16 A case study of BMD implementation in Louisiana, Lessons learned Dr. Louay Mohammad, LTRC Dr. Sam Cooper III, LADOTD Dr. Jay Winford, Prairie Contractors AAPT Office: 6776 Lake Drive, Suite 215 Lino Lakes, MN Phone: aapt@aapt.comcastbiz.net To register or for additional information please check our web site at:

26 High Friction Surface Treatments 29